Carriers are either common or private. Private carriers are persons who undertake for the transportation in a particular instance only, not making it their vocation, nor holding themselves out to the public as ready to act for all who desire their services. Allen v. Sackrider, 37 X. Y. 341. To bring a person within the description of a common carrier , he must exercise it as a public employment; he must undertake to carry goods for persons generally; and he must hold himself out as ready to transport goods for hire, as a business, not as a casual occupation . Alexander v. Greene, 7 Ilill (N. Y.) 564; Hell v. Pidgeon, (D. C.) 5 Fed. 634; Wyatt v. Irr. Co., 1 Colo. App. 480, 29 Pac. 006. A common carrier may therefore be defined as one who, by virtue of his calling and as a regular business, undertakes for hire to transport persons or commodities from place to place, offering his services to all such as may choose to employ him and pay his charges. Iron Works v. Hurlbut. 158 N. Y. 34. 52 N. E. 005, 70 Am. St. Rep. 432; Dwight v. Brewster. 1 Pick. (Mass.) 53, 11 Am. Dec. 133; Railroad Co. v. Waterbury Button Co.. 24 Conn. 479; Fuller v. Bradley, 25 Pa. 120; Mc- Duffee v. Railroad Co.. 52 N. II. 447. 13 Am. Rep. 72; Piedmont Mfg. Co. v. Railroad Co.. 19 S. C. 304. By statute in several states it is declared that every one who offers to the public to carry persons, property, or messages, excepting only telegraphic messages, is a common carrier of whatever he thus offers to carry. Civ. Code Cal. 5 210S; Civ. Code Mont.